Tension liquid spring



March 19, 1957 P. H. TAYLOR EIAL 2,785,887

TENSION LIQUID SPRING Filed March 16, 1954 2 Sheets-Sheet l IN V EN TOR. Fau Tayfor' and POZG7'7F Z umwaf March 19, 1957 P. H. TAYLOR ETAL 2,785,887

TENSION LIQUID SPRING Filed March 16, 1954 2 Sheets-Sheet 2 INVENTOR.

V Rafi '2? I gy/02' and 1 F0527? Zumwa Z1 United States Patent() TENSION LIQUID SPRING Paul H. Taylor, Grand Island, and Robert F. Zumwalt, Tonawanda, N. Y., assignors to Wales-Strippit Corpo: ration, North Tonawanda, N. Y., a corporation or New York Application March 16, 1954, Serial No. 416,472

4 Claims. (Cl. 267--1) The present invention relates to liquid springs, and more particularly to a liquid spring which is adapted to operate as a tension spring between two relatively movable parts.

In the past, liquid springs have been of the so-called compression type, and have been constructed so that the posed members place a compression on the spring as thesei members are tensioned.

Obviously, design of a cage suitable for a particular in-- stallation creates many problems. It adds a complexity to the spring unit. Moreover, it is often diflicult to utilize atensioning cage or adapter on many of the modern pieces of equipment where a tension spring is required.

While tension springs of the mechanical type are easily fabricated, because the resilient medium, a coil or a leaf spring, is readily subject to reversal so that it can be used either in compression or tension, it is obvious that in the case of a liquid the alternate to compression, namely, tension, merely reduces the pressure. In fact, the only pressure that could-possibly be realized by the tensioning of I the liquid would be that caused by atmospheric pressure opposingthe movement of the movable part of the spring infthedirectio nof tensioning.

videjatenSiOn type liquid spring which will require no cagebr adapterjfor it to function.

The primary. object of the present invention is to pro J 6 2,785,887 Patented Mar. 19, 19 57 arrows, and illustrating how the cylinder, in which the operating piston travels, is connected with the mam reservoir of the spring;

Fig. 3 is a fragmentary axial section, similar to Flg. 1, but showing the elements of the spring in their compressed or low load position; and

Fig. 4 is a side elevation of a spring built according to a modification of this invention, in its compressed or low load position, part of the spring being broken away to show the check valve for dampening the action of the spring in one direction.

Referring now to the drawings by numerals of reference, and first to the embodiment of the invention illustrated in Figs. 1 to 3 inclusive, 10 denotes a hollow cuplike container or receptacle having a bottom 11 and an outside cylindrical wall 12 which is integral with the bottom. The top or open end of the receptacle is closed by a plug member 14. Projecting forwardly from the bottom wall 11, and integral therewith, and extending through an opening in the plug member 14 is a cylinder 15. The cylinder 15 is disposed centrally of the receptacle or container and is concentric with the outside wall 12 of the receptacle or container. The cylinder 15 and outside wall 12 bound an annular chamber or reservoir 16 adapted to be filled with liquid L.

The particular configuration of container 10 and cylinder 15 shown is adapted to manufacture by the cold extrusion process in which both the receptacle or container and the cylinder 15 may be deep drawn. The plug member 14 may be brazed in place in tight, leak-proof engagement with the inside of the wall 12 and in leak-proof, tight engagement with the outside of the cylinder 15. The whole unit may be placed in a furnace, after assembly, and the plug member may be furnace-brazed to the receptacle 10 and cylinder 15 to close the annular chamber or reservoir 16 and form the main liquid containing portion of the spring.

Reciprocable in the cylinder 15 is a piston, denoted as a, whole at 20. This piston comprises a shaft member or sleeve 21, a piston head or cap member 22, and a seal 23. The piston head or cap member 22 closes the inner end of the sleeve or shaft member 21, threading into the bore of this sleeve or shaft member. It provides a seat against which the seal 23 engages. The seal 23 is preferably of the type disclosed in the pending application of Charles Lee Rovoldt, Serial No. 298,094, filed July 10, 1952,

' Another object of this invention is to provide a tension type liquid spring in which the liquid of the spring is com pressed when the spring is in tension.

type liquid spring which can be preloaded.

'A further object of the invention is to provide a tension '50 Another object of the invention is to provide a tension 2 now Patent No. 2,708,573, granted May 17, 1955. This seal comprises a nylon sleeve 24, and a rubber O-ring 25 that seats in an annular groove in the front face of seal 23.

.The outer or forward end of the cylinder 15 is closed by'a seal 28 similar in construction to the seal 23 and comprising a nylon sleeve 29 and an O-ring 30. The seal 28 is reversed with reference to the seal 23 and is mounted in opposed relation thereto. Seal 28 is retained in the bore 35 of the cylinder 15 by a nut 36 which threads on to the outer, protruding end of the cylinder 15.

In the compressed position of the spring, shown in Fig.

3, both the cylinder 15 and the chamber 16 are filled with a compressible liquid L such as, for instance, a liquid having a silicone base. Liquids may be provided for this after from the specification and from the recital of the appended claims.

In the drawings:

Fig. 1' is an axial-section of a liquid tension springconstructed acco'rdi'ng -to one embodiment'of this invention, and showing tlie'spriiig in extended position;

Fig.2 is a transverse: section through this spring taken on. theli-ne 2-2 of Fig. -l looking-in the direction of the purpose which have a compressibility by volume of 12% at 20,000 p. s. i. The bore 35 of the cylinder 15 is in communication with the chamber 16 through a duct or passage 40 that extends rearwardly through the wall of the cylinder 15 from. bore 35 into chamber 16.

Tensioning of the',spring is eifected by outward movepart, for instance, to the flight deck of an aircraft, carrier by a pin 45. A movable part, whose movement is to he resiliently restrained by the, spring, such as the airplane stop ing ble or wire 48 of the carrier, i s con; necte'd to the pistonitl as, fgr instance, by means of the pin-eye 46. The shank of this pin-eye threads into the outer. end: at the h re i h st shaf member or leeve. 2 T e len th. of he swing be a d b adjusting the pin-eye in the sleeve 21 lg v s nror cle sto. sec r th i -e n an d u ted; psit o A top bolt .9 whi h ads adiilstably a i s nns and into a hole 51 in the bottom 11 of the receptacle, serves limit outward avel t he Pis on. The Shank of thislbo tpassestlt o l h a hole n, he. nisto head 2.2.; and he head .2. ofi his b9 t is ad pted. engagethe. ou er; rforwan en of member 2.2-

Obviously, as the piston 20 movesoutwardlyfrom the posit on hown n igoward tha -o ig. he compressihlejliq id in... he cylinder. 15-min. he forced; out. of that, cylinder through. the passage. 49 into the. reservoir onchamher L compressingtheliquid; in .thereservoin or. chamber. Asthescal. 'Qlosesolf,thepassageAfl, the. outward.- travel. of; the piston is, dashrpotted Finally, if the boltStl-permitssuflicientoutward travel of the piston. for, the.scal;. 2.3, to. close, oii the passage. 44), liquid. will; be. entrapped between the seals. 2.3-, andlS; and.the.entrap.- ment ofthisliquid,togetherwith the. bolt 50W will. stop heoutward: tramlofthe. piston. Preferably, however,

the. outward travellof thepiston will be, stoppedbefore.

the .seal23 closes off completely. the passage 40. Upon release of the tension force appliedto thepiston 20 :by fllitjelel'nent 48; througln the'eyeapin. 46, the. resiliency of-theiliquid L; in thechamber. 16-.andbetweenv the seals 23 .and;2-8-will causethepistoh tobe moved to, its retracted position shown in Fig. 3.

Itri s,.sometiniesdesirable in a spring of this type to restricp the. passage of liquidfrom the cylinder 15 into thereservoir. 16. so as'further to decelerate the travel of the, springin. the 'tensioning direction. For this; purpose, a.checkvalveofiflmaybe employed as shown in Fig 4. The check valve shownv comprises a ball 61, a coil springl62lacting against the ball, and a nut-63 for adjusting the loading of the spring. The; nut-hasa duct 64.,therethroughQ The: wall of the cylinder 15 isof increased-thickness, as compared with. the thickness of the Wall ofsthe cylinder 15 0f Fig. l, in order to provide suit; able mounting for this check valve. The passage 40. betweenlthebore35 of-the cylinder 15 and the chamber. 16?- Of'rthfl containerorreceptacle li) of Fig. 4. is

reduced iridiameter at-itsinner or rear end,; as denoted.- attia so that a seat will beprovided for the ball 61 in, the. passageway. A bleed (s1 lay-pass groove 66 is machinedgthro igh the seat A at one side of the passageway to. allow-limltedpassageofliquid past the check valve as.

thetpiston-lll is'ex tend ed; Thus the rate of travel of the;

piston on its tensioning stroke is restricted while at the same tune providingthe resiliency which is essential to cushioningpofgthe tensioning force. In the retracting stroke of-the piston, however, the ball 61 is forced ofi its; seat; and the liquid can pass freelyfron the chamber.

or..reser.voir 16' intothe cylinder 15f so that thepiston can .be. retracted at the highest possible velocity.

Obviously, reversal 'of lt'he' check valve will allow free flow-.ofi the-.fliquid during tensioning of the spring, but

restricttitsfmovenient during retraction. Obviously, also, by.-,var.ying thesize of the bleed grooves, or the number ofisuchigrooves, fur-then control over the rate of movement .of-tthepiston. in either direction can ,be obtained}:

While .the invention has been described in connection with different embodiments thereof, it will beunderstood that itsis capable of further modification; and this apmliv cation is intended tqcover any variations, uses, oradaptations-of the: invention following in general the principles,

of the invention and including such departuresffiomthe present'disclosure as come within known or Customary practice in the artto:which the invention pertaina and check valve on said outwardtainerand centrally disposed. within said container and.

projecting forwardly from. the bottom. thereof outwardly through an openingin said cover, said cylinder being secured around its whole periphery to said cover-and forming with said. container an annular reservoir-surrounding said cylinder, a piston reciprocal in said cylinder, a seal carried by said piston for sealing' against leakage of liquid between said piston and said cylinder as the piston reciprocates in the cylinder, sealing means secured in said cylinder at the. outer end: of said: cylinder:- andxthrough which. saidpiston passes; for. sealingagainst leakage of liquid fromsaid cylinder, aduct:connectingsaid reservoirwith said cylinder and lying between the front face-pf said. seal and said sealingmeans. when said piston is in itsinner position in said cylinder, and a1compressibleliquid filling said cylinder, duct, and: reservoir to be compressed onoutward movement of saidpiston, and means for limitingoutward movement'oflsaid piston to prevent engagement of said seal with said sealing means.

2. A.tension liquid springcomprising-a hollow, cupshaped container closed at-its bottom,- acoverclosingthcopposite end of said container andsecuredto said container around itsperiphery against leakage. ofliquid from said container, a cylinder integral withsaid; container and centrally disposed within said container and" projecting forWardlyfrom-the bottom thercofgoutwardly throughanopeninginsaid cover, said cylinderbeingsecured around its whole periphery to said cover and forming with said container'an .annular'reservoir' surrounding said cylinder, at piston-reciprocalin said cylinder, a duct connecting said reservoir with saidcylinder and lying between the front face of saidgpiston and the outer end'of said= cylinder when said piston is in its inner position in said cylinder, and a compressible liquid filling said cylinder, duct, and reservoir to be compressedon outward movement of" said piston, means carriedbysaid. piston for sealingagainst leakage of liquid I between said piston and cylinder as the piston recipqrtJqzates in thecylinder, and sealing means secured in said cylinder at the outer end of said cylinder and through which said-pistonpasses and sealing against leakage of'liquid; frorn said cylinder.

3. A tension liquid spring'comprisinga hollow, cupshaped -container closed at; its bottom and ,adapted to be. cover.

secured-to one oftwo relatively. movahlepagtsg I closing the opposite end of? said container,; a.-,cy.lin der integral "with said'container andj disposed. centrally within 7 said container and projecting forwardly from. the bottom thereof' outwardly through an openingjn said cover,

when said piston is in its inner position-; in:;said'& cylinder,

a compressibleliquid filling saidcylinder,- duct,- andtreservoi r-tol. becompressed on outward movement. .of; said piston, a check valve closing said duct againstapassageot liquid therethrough on outward movement -of -said piston. nd, a ble ust; fQr l wingtrestrictedtpassage-of; liquid ween. d: se v ir;

with said container, a passage establishing communication between said reservoir and said cylinder adjacent the outer end of said cylinder, a hollow piston reciprocal in said cylinder and projecting outwardly of said cylinder, a pair of spaced seals within said cylinder and surrounding said piston, one of said seals being mounted on said piston to travel therewith to seal against leakage of liquid between said piston and said cylinder as said piston reciprocates in said cylinder, the other of said seals being stationary relative to said piston and being secured at the outer end of said cylinder to seal against leakage of liquid from said cylinder, said piston projecting outwardly through the latter seal, and a bolt secured to said container and passing through said piston and 5 ward travel of said piston.

References Cited in the file of this patent UNITED STATES PATENTS Orloff Jan. 1, 1952 Tipper July 29, 1952 FOREIGN PATENTS 641,527 Great Britain Aug. 16, 1950 

